She said: "I also have a walk-in closet - a room 6ft by 3ft - and all that is in there are my newspaper and magazine clippings on the royal family.

"I first saw the Queen in 1971 when I was two-and-a-half. Since then I have seen her four times, and I managed to give her a bouquet of freesias, and then afterwards had my picture in the local paper and in a national newspaper."

She recalled one occasion when she drove herself and her three children six hours to see Prince Charles and his sons.

Lisa's obsession with the Royal Family revolves around the Duchess of York. She says Fergie is her favourite person, and that she treasures photos and home videos shot when she met her.

Californian Lisa Mundy meets her heroine at a Dieting with the Duchess booksigning

As a live-in nanny, 34-year-old Lisa has just one room, which is crammed with Fergie memorabilia, including dolls, porcelain, signed books and T-shirts, stickers, toys and newspaper cuttings.

And as a devoted Weight Watcher, she not only lost 57lbs, but received a note of encouragement from the Duchess.

She told BBC News Online that she was in London in 1986 for the wedding of Sarah Ferguson and Prince Andrew.

Lisa's Fergie wedding doll

She added: "I met her at a book signing on 21 January - it was a total dream come true. I stood in line for over five hours and was first in line.

"I had on a sweatshirt with her picture on it and the words 'Surviving Life' on top and then underneath 'Sarah Style'. She signed this wonderful piece for me and now it is hanging in a custom-made frame in my room.

"After the book signing I saw her car on the car park and recognised it. I walked past the car with my friend, and we just saw her coming.

"She was so nice and warm she stopped and gave me a hug, and for that moment, I was the happiest person.